Deep in the bowels of nerds' paradise a battle is being staged. Mythical beings wield their mighty swords, belly dancers shimmy and costumes get tangled up. Although comical at times, cosplay is serious business.
About 200 ardent fans show their support by screaming loudly and often. A panel of four judges takes notes on performances that are based on manga, cartoons and online games. It's like a cross between charades and a fantasy talent show.
More than 50 groups of up to 32 role players turn up to present their tableaux at a Zhongguancun electronics mall basement, in Beijing's Haidian district, also known as "China's Silicon Valley".
In an environment of shoot-'em-up games, vigorous Wii demonstrations and electronic accessories, the ChinaJoy Cosplay Carnival preliminary contest for Beijing is in full swing.
The group Pink Monkey Heaven's elaborate role-playing performance, based on the online game Ragnarok, is one of the highlights. It begins with five girls dressed in Arabian Nights-themed costumes, gauzy skirts and golden bras, posing under golden wings.
Spice sells and the crowd wants more. Photographers fight for position. Organizers wade in and try to eject the amateurs, insisting they need a media pass, but then give up. A fresh set of cosers troop onto the stage, wave their weapons and vogue.
The judges - government officials and website editors - award marks for the standard of the performances and similarity to the original characters.
Pink Monkey Heaven scores 85.6 and comes second, just 0.4 of a percentage point behind eventual winner Yi You Comic Club, but the group's chairperson, Wan Wan, is satisfied with the result.
"It's not so important because it's just a preliminary, so we will concentrate on the next round and national contest," she says.